Increasing 4H-SiC Trench Depth by Improving the Dry Etch Selectivity towards the Oxide Hard Mask

Oleg Rusch; Kevin Brueckner; Johann Tobias Erlbacher

doi:10.4028/p-1PoMgV

Paper Titles

Increasing Mobility in 4H-SiC MOSFETs with Deposited Oxide by In-Situ Nitridation of SiC Surface
p.157

Demonstrating SiC In Situ Rounded Trench Processing Technologies for Future Power Trench MOSFET Applications
p.163

High Mobility 4H-SiC P-MOSFET via Ultrathin ALD B₂O₃ Interlayer between SiC and SiO₂
p.171

Quality Improvement of SiC Substrate Surface with Using Non-Abrasive CMP Slurry
p.181

Addition of Transition Metal Ion CMP Slurry for Forming Ultra-Flat SiC Crystal
p.187

Increasing 4H-SiC Trench Depth by Improving the Dry Etch Selectivity towards the Oxide Hard Mask
p.193

A Comparison between Different Post Grinding Processes on 4H-SiC Wafers
p.201

Influence of Active Area Etching Method on the Integrity of Gate Oxide on 4H-SiC
p.211

High-K Gate Dielectric for High-Performance SiC Power MOSFET Technology with Low Interface Trap Density, Good Oxide Lifetime (t_tddb≥ 10⁴s), and High Thermal Stability (≥ 800 °C)
p.217

HomeSolid State PhenomenaSolid State Phenomena Vol. 359Increasing 4H-SiC Trench Depth by Improving the...

Increasing 4H-SiC Trench Depth by Improving the Dry Etch Selectivity towards the Oxide Hard Mask

Abstract:

This work presents the results of process development for trench formation in SiC power devices to increase the trench depth by improving SiC/SiO₂-selectivity of the dry etch process. Motivation behind this development is to further improve the electrical properties of conventional devices like SiC MOSFETs by implementing a trench geometry, allowing the cell pitch to be increased, leading to a reduced on-resistance of SiC TrenchMOS devices. Trench etching was performed on 4H-SiC substrates by utilizing an oxide hard mask, patterned by photolithography and dry etching. The SiC trench profile was analyzed by cross-section preparation via FIB and SEM imaging. The highest SiC/SiO₂-selectivity achieved was 7.9, with SiF₄ gas flow being the most decisive parameter for it. With that, the selectivity of the standard SiC trench etch process was increased by nearly five times. SiC trenches with depths of 5 µm could be demonstrated. However, then the structural fidelity was deteriorated, with micro-trenching and sidewall bowing being the largest limitations regarding applicable trench depth in SiC power devices.

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Periodical:

Solid State Phenomena (Volume 359)

Pages:

193-200

DOI:

https://doi.org/10.4028/p-1PoMgV

Citation:

Cite this paper

Online since:

August 2024

Authors:

Oleg Rusch*, Kevin Brueckner, Johann Tobias Erlbacher

Keywords:

4H-SiC, Dry Etching, FIB, ICP, Selectivity, Trench, TrenchMOS

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Creative Commons CC BY 4.0

Citation:

* - Corresponding Author

References

[1] J. Millan, P. Godignon, X. Perpina, A. Perez-Tomas, J. Rebollo, A Survey of Wide Bandgap Power Semiconductor Devices, IEEE Trans. Power Electron. 29 (2014) 2155.

DOI: 10.1109/tpel.2013.2268900

Google Scholar

[2] F. Udrea, G. Deboy, T. Fujihira, Superjunction Power Devices, History, Development, and Future Prospects, IEEE Trans. Electron Devices 64 (2017) 713.

DOI: 10.1109/ted.2017.2658344

Google Scholar

[3] T. Kimoto, J.A. Cooper, Fundamentals of Silicon Carbide Technology, first ed., Wiley, Singapore, 2014.

Google Scholar

[4] S.M. Sze, M.K. Lee, Semiconductor Devices, Physics and Technology, third ed., Wiley, New York, 2012.

Google Scholar

[5] D. Widmann, H. Mader, H. Friedrich, Technologie hochintegrierter Schaltungen, second ed. Springer, Berlin, 1996.

DOI: 10.1007/978-3-642-61415-6

Google Scholar

[6] N. Posseme, Plasma Etching Processes for CMOS Device Realization, London, Kidlington Oxford: ISTE Press Ltd; Elsevier Ltd, 2017.

Google Scholar

[7] B.J. Baliga, Silicon Carbide Power Devices, first ed., World Scientific Publishing Co, Singapore, 2005.

Google Scholar